Image acquisition apparatus for use with a microscope, an image recording system that uses the image acquisition appartatus, and an image storage method

ABSTRACT

An image acquisition apparatus is disclosed that includes: an image pickup element that acquires images obtained using a microscope; a change detector that detects the amount of change between an image acquired by the image pickup element and a subsequent image acquired by the image pickup element; and a data-reduction processor that enables reduced-data images to be output, as well as images that have not been subject to data reduction or that have been subject to a different rate of data-reduction depending on the amount of change detected by the change detector. An image recording system that uses the image acquisition apparatus is also disclosed, as well as an associated method.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of priority of JP 2005-027784, filedFeb. 3, 2005, the contents of which are hereby incorporated byreference.

BACKGROUND OF THE INVENTION

The present invention relates to an image acquisition apparatus for usewith a microscope, an image recording system that uses the imageacquisition apparatus, and an image storage method. More specifically,the present invention relates to an image acquisition apparatus for usewith a microscope, a microscope system that uses the image acquisitionapparatus and stores image data, and an image storage method wherein anappropriate storage procedure is performed depending on the amount ofchange detected when successively acquired images of a specimen arecompared.

Conventionally, in order to store images of objects observed by amicroscope, utilization has been made of a method of photography thatemploys a silver salt film camera. Recently, methods of photographingobjects utilizing electronic cameras (termed ‘digital cameras’) havebecome popular.

In the medical and science sectors, multiple applications have beenprovided that observe living cells as an object and, in order to observechanges of the living cells over time, imaging apparatuses formicroscopes (i.e., microscope cameras) have been developed that recordwhat will be termed herein as ‘ordinary’ motion picture images (whereinmotion picture images are successively acquired at the normal rate formotion pictures over a continuous period, as in an ordinary movie), aswell as apparatuses for microscopes that record time-lapse photographyimages, and the like.

Generally, in executing motion picture recording, time-lapse photographyrecording, and so on, the amount of photographic image data obtained islimited by the storage capacity of the storage medium that is to storethe photographic image data, and the needless consumption of storagecapacity is to be avoided since it increases costs. Thus, a photographicdevice for use with a microscope has previously been developed thataccomplishes detailed storage of only the required image data. It doesthis by “thinning” unnecessary image data from among photographed imagedata, as described in Japanese Laid-Open Patent Application No.H10-66074.

However, in a photographic apparatus that performs ordinary motionpicture recording of images, it is preferred that the frame rate not bereduced. Therefore, in order to reduce the amount of image data duringordinary motion picture recording, various techniques have been appliedwhich change (i.e., lower) the resolution of the recorded image (e.g.,by compressing the image data). As a result, images desired by anobserver and in which living cells change in appearance over a shortperiod of time may not be recorded with an adequate resolution orpicture quality.

Furthermore, in terms of a desired visual phenomenon to be recorded,recording of images has generally been accomplished wherein a specimenimage is obtained in some manner in order to provide an image havingadequate resolution and picture quality. In the case of increasing thedegree of resolution and accomplishing ordinary motion picturerecording, if the period in which an observed object generates a desiredphenomenon is short relative to the period of photographic recording,the majority of the data obtained will have an unnecessarily high degreeof image resolution, resulting in the capacity of the storage mediumbeing needlessly consumed.

BRIEF SUMMARY OF THE INVENTION

The present invention provides an image acquisition apparatus for usewith a microscope, an image recording system that uses the imageacquisition apparatus, and an image storage method that iscomputer-implemented. In the image acquisition apparatus and in theimage recording method of the present invention, the acquisition ofimages (and hence the subsequent recording of the acquired data) is madedependent on the amount of change between two images that arephotographed at different times.

The image recording method of the present invention acquires successivephotographic images of a specimen observed by a microscope, detects theamount of change between two images of the specimen acquired atdifferent times and, depending in part on the amount of change that isdetected, either performs image processing to reduce the number ofpixels acquired so as to reduce data storage requirements or performs noprocessing so that a high quality image may be recorded during periodswhen the appearance of the specimen changes. Either motion pictureimages or time-lapse photography images may be recorded using therecording system and method of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description given below and the accompanying drawings, whichare given by way of illustration only and thus are not limitative of thepresent invention, wherein:

FIG. 1 is a block diagram that shows the components of Embodiment 1 of amicroscope system that includes a photographic unit 102, a signalprocessor 103, a change detector 104, a pixel number converter 105, andother components;

FIG. 2 is a block diagram that shows the components of the photographicunit 102 shown in FIG. 1;

FIG. 3 is a block diagram that shows the components of the signalprocessor 103 shown in FIG. 1;

FIG. 4 is a block diagram that shows the components of the changedetector 104 shown in FIG. 1;

FIG. 5 is a flowchart that shows the successive photographic processsteps executed by the microscope system 100 of the first embodiment;

FIG. 6 shows the data format types that may be output from the pixelnumber converter 105 shown in FIG. 1 depending on a selection signal SELand a comparison result signal K;

FIG. 7 illustrates how the frame-integrated value S of the illuminationdifference that is calculated and output from the difference detector402 shown in FIG. 4 changes with frame number, when there is a change inspecimen state during some of the frames, in the case of motion picturerecording;

FIG. 8 shows the state of the output image signal corresponding to theselection signal SEL and the comparison result signal K in the casewhere the selection signal SEL is set for the thinning mode ofreduced-data image acquisition;

FIG. 9 shows the state of the output image signal corresponding to theselection signal SEL and the comparison result signal K in the casewhere the selection signal SEL is set for the binning mode ofreduced-data image acquisition;

FIG. 10 is a block diagram that shows the components of Embodiment 2 ofa microscope system that includes a photographic unit 102, a signalprocessor 103, a change detector 104, a pixel number converter 105, andother components;

FIG. 11 shows the relationship between the relative amount ofillumination light required during binning processing (K=0) versus noprocessing (K=1) according to Embodiment 2;

FIG. 12 is a block diagram that shows the components of a changedetector 104A of a microscope system according to Embodiment 3;

FIG. 13 shows a scaled display image that may be displayed on thedisplay 109 shown in FIG. 10;

FIG. 14 is a block diagram that shows the components according toEmbodiment 4 of a microscope system of the present invention;

FIG. 15 shows the relative image compression ratio that depends on thecomparison result signal K in Embodiment 4;

FIG. 16 is a block diagram that shows the components of Embodiment 5 ofa microscope system according to the present invention;

FIG. 17 is a table that illustrates the frame thinning status versus thetwo possible values of the comparison result signal K in Embodiment 5;

FIG. 18 illustrates how the frame-integrated value S of the illuminationdifference that is calculated and output from the difference detectorwithin the change detector 104 shown in FIG. 16 changes with framenumber when there is a change in specimen state during some of theframes;

FIG. 19 as a block diagram that shows the components of a changedetector 104B of a microscope system according to Embodiment 6 of thepresent invention;

FIG. 20 illustrates the manner in which the frame-integrated value S ofthe illumination difference that is calculated and output from thedifference detector within the change detector 104B of FIG. 19 changeswith frame number during successive frames at a time of bright fieldobservation; and

FIG. 21 illustrates the manner in which the frame-integrated value S ofthe illumination difference that is calculated and output from thedifference detector within the change detector 104B of FIG. 19 changeswith frame number during successive frames at a time of fluorescentlight observation.

DETAILED DESCRIPTION

A description of Embodiments 1-6 of the invention will now be providedwith reference to the drawings.

Embodiment 1

As shown in FIG. 1, a microscope system 100 includes: a microscope 101that is capable of switching to different types of observation, such astransparent field observation or fluorescent light observation; aphotographic unit 102 that forms a relayed image of a specimen that isimaged by the microscope 101; a signal processor 103; a change detector104; a pixel number converter 105; a controller 106; an interface 107; apersonal computer 108 (hereinafter, PC 108); a display 109; an inputapparatus 110; and a central processing unit 112 (hereinafter, CPU 112).Also, the CPU 112 is electrically connected to the photographic unit102, the signal processor 103, the change detector 104, the pixel numberconverter 105, and the controller 106.

As shown in FIG. 2, the photographic unit 102 includes: a photographiclens 201; an image pickup element 202 such as in an ordinary CCD camera;a known double correlation sampling (CDS)/automatic gain control (AGC)circuit 203 (that performs noise removal and level adjustment, and ishereinafter referred to as ‘CDS/AGC circuit 203’); an A/D converter 204;and a drive 205 (which, for example, may be a TGV drive). An image of aspecimen that is obtained using the microscope 101 is input into thephotographic unit 102, and is relayed onto the image pickup element 202by the photographic lens 201. The drive 205 is electrically connected tothe image pickup element 202, and a control bus 111 carries drivesignals in order to drive the image pickup element 202 in a mannerdetermined by the CPU 112 (FIG. 1). For example, the drive 205 mayoutput drive signals to the image pickup element 202 in order toaccomplish reduced-data image acquisition in the binning mode, in whichcase the light exposure converter of the image pickup element 202 (inresponse to a signal from the CPU 112) calculates and reads out, as onepixel, cumulative image data of multiple adjacent pixels (such as fourpixels that, before read-out, form a 2×2 array). The image pickupelement 202 photo-electrically converts the incident light correspondingto any of the drive signals from the drive 205.

The photo-electrically converted signal passes through the CDS/AGCcircuit 203 and, after being converted into a digital signal by the A/Dconverter 204, it as well as a synchronization signal that providesframe cycle timing are output to a signal processor 103.

As shown in FIG. 3, the signal processor 103 performs image adjustmentprocessing of black balance (BB) correction 301, white balance (WB)correction 302, and the like, on the input image data in response to asetting signal from the CPU 112 that is communicated via the control bus111 and an internal bus. In addition to outputting image data to thepixel number converter 105 (see FIG. 1), the signal processor 103outputs a synchronization signal and an image data signal to the changedetector 104 (see FIG. 4). In addition, an automatic exposure evaluationunit 303, in order to calculate the exposure time, calculates anecessary exposure value (AE) by integrating the illumination over eachframe and transmits it to the CPU 112.

As mentioned above and illustrated in FIGS. 3 and 4, the image datasignal and a synchronization signal from the signal processor 103 areinput to the change detector 104. The image data signal is input in itsexistent state into one input of a difference detector 402 and, afterbeing delayed one frame by means of a frame delay unit 401, is alsoinput into another input of the difference detector 402.

The difference detector 402 calculates the illumination difference ofthe image data signal for pixels of the current frame (i.e., the imagedata signal input in its existent state from the signal processor 103versus that of the previous frame (i.e., the frame image data signalafter being delayed one frame by the frame delay unit 401). Using theinput synchronization signal, it calculates the frame-integrated value Sof the illumination difference signals for each frame, and the signal Sis then output to a threshold value discriminator 403.

The threshold value discriminator 403 is electrically connected to theCPU 112 by the control bus 111, and a comparison is made by the CPU 112between a pre-established threshold value Th and the value S, thecomparison result of which is sent to the CPU 112 as a comparison resultsignal K. More specifically, if the frame-integrated value S of theillumination difference is greater than or equal to the threshold valueTh (i.e., S≧Th), a “1” is output as the value of K; and if theframe-integrated value S of the illumination difference is smaller thanthe threshold value Th (i.e., S<Th), a “0” is output as the value of K.

The pixel number converter 105 outputs to the controller 106 either theinput image or a reduced-data image that it creates by thinningprocessing in which the total number of pixels is reduced by a factor of4 (termed ‘¼ thinning’).

Controller 106 is electrically connected to the PC 108 through theinterface 107, and to the CPU 112 through the control bus 111.Conversion of the data format is accomplished, and timing adjustment ofthe photographic data transmission/reception signal is accomplishedbetween the PC 108 and the CPU 112. In addition, the controller 106 iselectrically connected to the pixel number converter 105, and the imagedata input from the pixel number converter 105 is transmitted to theinterface 107.

The interface 107 is provided with an internal buffer memory, and timingadjustment is performed of data communication between the PC 108 and thecontroller 106. A display 109 and an input apparatus 110 areelectrically connected to the PC 108.

The display 109 comprises a monitor such as a TFT display, a CRT, etc.An image is displayed on the monitor corresponding to an output imagesignal from the PC 108. The input apparatus 110 is electricallyconnected to the PC 108 and may comprise various devices such as akeyboard, mouse, etc. In addition, the input apparatus 110 may alsoinput photographic timing data to the PC 108.

An explanation will now be provided of the operations executed by themicroscope system 100 of the present embodiment.

FIG. 5 is a flowchart that shows the flow of the photographic processesthat may be executed by the microscope system 100.

First of all, once electric power has been connected to the microscopesystem 100, the microscope system 100 is turned ON in step S501, and thePC 108 transmits image data to the CPU 112 through the controller 106 inorder to acquire a specimen image, with the default photographicconditions being maintained in an internal storage device.

In step S502, the CPU 112 transmits control parameters through thecontrol bus 111 in order to accomplish photographic recording using theimage data received from the PC 108.

In step S503, there is a wait period until the receipt of a previewimage command and, when notification is provided from the inputapparatus 110 to the PC 108 to the effect that the display of previewimages should commence, the PC 108 transmits a signal to the CPU 112indicating that the display of preview images should start. Once this isdone, in step S504, the display of preview images is begun.

The following detailed explanation is provided concerning the display ofpreview images. The CPU 112, upon receiving the signal to commence thedisplay of preview images, directs the drive 205 to commence acquiringimage signals. The drive 205 receives the directive and generates adrive signal that is transmitted to the image pickup element 202.

The image pickup element 202, following receipt of the signal from thedrive 205, photo-electrically converts a relayed image from themicroscope 101 that is incident thereon and outputs a signal. In thisinstance, in response to a directive from the CPU 112, a drive signalfor outputting all of the pixels of the image pickup element 202 is sentfrom the CPU 112. Thus, the image pickup element 202 photo-electricallyconverts the incident light for all available pixels. Subsequently, theoutput signal of the image pickup element 202 passes through the CDS/AGCcircuit 203 and, after being converted to digital data by means of theA/D converter 204, is sent to the signal processor 103. In the signalprocessor 103, image data (which has been processed for white balancecorrection and black balance correction as discussed above) is output tothe change detector 104 and the pixel number converter 105. However, atthis time, the change detector 104 is not operational.

The pixel number converter 105 transmits the input image data in itsexistent state to the controller 106. The controller 106, whileaccomplishing timing adjustment of the PC 108 through the interface 107,transmits the input image data to the PC 108 which, after converting theinput image data to a signal used by the display 109, transmits it tothe display 109, on which the specimen image is displayed. The aboveoperation is repeated so as to continuously display preview images ofthe specimen on the display 109.

In step S505, there is a wait period until receipt of an image conditionchange command. If no such command is received within the wait period,flow progresses to step S507. When a directive is sent from the inputapparatus 110 to the PC 108 indicating that there is a change in thephotographic conditions (such as white balance, exposure, etc.), in stepS506 the CPU 112 establishes a change in the control parameters based onthe image data received from the PC 108 and the display of previewimages is changed accordingly.

In step S507, when a directive is received by the PC 108 from the inputapparatus 110 to accomplish reduced-data image acquisition using one ofthinning mode processing and binning mode processing, or when adirective is received to commence either motion picture acquisition ortime-lapse acquisition of images for a specified amount of time, the PC108 transmits image data via the interface 107 to the CPU 112.

In step S508, the CPU 112 transmits a threshold value Th correspondingto the read image data to the change detector 104, and a selectionsignal SEL that selects the type of reduced-data acquisition (i.e., thethinning mode or binning mode) is sent to the pixel number converter 105and the drive 205 that is provided in the photographic unit 102. In thisinstance, if the binning mode is selected, a drive 205 outputs a drivesignal to accomplish reduced-data photographic acquisition using thebinning mode, and the exposure time is reduced by a factor of 4.Moreover, a directive for either of thinning mode processing or binningmode processing during reduced-data image acquisition may bepre-established so as to invoke reduced-data image acquisition, or not,depending upon the illumination level (i.e., the brightness) of theimage data of one frame.

In step S509, the PC 108 starts an internal timer and simultaneouslytransmits a control signal that directs the commencement of imageacquisition of images intended for recording to the CPU 112, at whichtime the change detector 104 commences operation. Also, a signal inwhich incident light of the image relayed from the microscope 101 isphoto-electrically converted by the image pickup element 202, isprocessed in the same manner as when accomplishing the display ofpreview images, and is output to the pixel number converter 105 and thechange detector 104.

As discussed above, the change detector 104 calculates the value S forthe input images of two frames in the difference detector 402. In thethreshold value discriminator 403, a comparison is made with thethreshold value Th that is established in the CPU 112. If the value of Sis greater than or equal to the threshold value Th, the comparisonresult signal K is made to be “1” and is sent as a digital signal to theCPU 112; otherwise the comparison result signal K is made to be “0” andis sent as a digital signal to CPU 112. Also, in the initial firstframe, since there is no data from the previous frame, a comparisonresult signal K of “0” is output.

The CPU 112 acquires the comparison result signal K for each frame. Whenthe selection signal SEL is set to the binning mode and the comparisonresult signal K is “1” (i.e, the integrated value of the framedifference is determined to be greater than or equal to an establishedthreshold value Th), the drive 205 (FIG. 2) is controlled, and the drivesignal of the image pickup element 202 of the following frame is set inthe same manner as when accomplishing the display of preview images(i.e., full image-data acquisition). In addition, when the selectionsignal SEL is set for the binning mode and the comparison result signalK is “0”, a drive signal is generated to accomplish image acquisition ofthe subsequent frame in the binning mode.

The CPU 112 transmits a control signal to the pixel number converter105. In the change detector 104, if the value of S is determined to besmaller than the established threshold value Th (i.e., if K equals “0”),and if the selection signal SEL is set for the thinning mode ofprocessing, an image is generated in which the number of pixels isreduced by thinning processing; on the other hand, if the integratedvalue of the frame difference is determined to be greater than or equalto the established threshold value Th (i.e., if K equals “1”) and if theselection signal SEL is set for the thinning mode of processing, animage is acquired as when accomplishing the display of preview images(i.e., no thinning processing occurs).

FIG. 6 summarizes the data format that is output by the pixel numberconverter 105. As discussed above, the selection signal SEL and thecomparison result signal K determine the data format that is output bythe pixel number converter 105.

The controller 106 transmits image data to the PC 108 whileaccomplishing timing adjustment of the PC 108 through the interface 107.For example, in the instance of there being a directive for time-lapseacquisition of acquired images, the PC 108 obtains the directed inputimage data at the directed intervals and, after conversion to aspecified still image format, preserves the images in an internalstorage apparatus. The operation extending from the above-discussedphotography to storage in an external storage apparatus or an internalstorage apparatus of the PC 108, is repetitively performed.

In step S510 the PC 108 detects whether the duration for photographicacquisition of images intended for recording (as indicated by theinternal timer) has elapsed. If so, in step S511, the PC 108 convertsthe acquired image data to a specified format. The data may then bestored in an internal or external storage apparatus (not illustrated),and the series of operations is suspended since photographic recordinghas thus been completed.

An explanation will now be provided concerning the operation ofEmbodiment 1.

FIG. 7 illustrates how the frame-integrated value S of the illuminationdifference (i.e, the signal that is calculated and output from thedifference detector 402 shown in FIG. 4 in the case of the display ofpreview images) changes over different frames when there is a change inspecimen state during some of the frames. The frame number is plotted onthe horizontal axis and the values of S and Th are plotted on thevertical axis. In this instance, since the threshold value Th isexceeded in frame numbers 5-8, a value of K equals “1” will be outputfrom the threshold value discriminator 403 during those frames. For theother frames illustrated, a value of K equals “0” will be output. Inthis instance, during frames 5 to 8, there is great change in the imageillumination value, and the state of the specimen is determined to be ina period of change in comparison to other periods.

FIG. 8 shows the state of the output images (thinning processing or nothinning processing) of acquired images in frames 1-12 when theselection signal SEL is set for thinning processing of the acquiredimage data and when the K values for frames 1-12 correspond to thoseshown in FIG. 7 (i.e., with K equal “1” for frames 5-8 and “0”otherwise).

FIG. 9 shows the state of the output images (binning processing or nobinning processing) of acquired images in frames 1-12 when the selectionsignal SEL is set for binning processing of the acquired images and whenthe K values for frames 1-12 correspond to those shown in FIG. 7.

As can be seen in FIGS. 8 and 9, when a frame subsequent to when theoutput results of the threshold value discriminator 403 are such thatK=1 (i.e., when the change in the specimen state is determined to berelatively great), the acquired image will be output withoutreceded-data processing (i.e., as in the case of for preview imagedisplay). On the other hand, if the output results of the thresholdvalue discriminator 403 are such that K=0 (i.e., when the change in thespecimen state is determined to be relatively small), in the subsequentframe an image is output in which the number of pixels (as compared tothe number of pixels output during preview image display) is reducedeither through thinning processing or binning processing, depending uponwhether thinning mode processing or binning mode processing has beendesignated. If binning mode processing has been designated (wherein theillumination value for each output pixel is determined by additionprocessing of proximate pixels of the input image), the illuminationvalues of the output will necessarily be large in comparison to theillumination values output in thinning mode processing. This enables theexposure time to be shortened and the frame rate to be increased.

Furthermore, according to Embodiment 1, in acquiring images for motionpicture recording or time-lapse photography recording during periods inwhich the change in appearance from a prior frame is determined to besmall, a photographic image is acquired in which the number of pixelelements in the photographic image is reduced. On the other hand, duringperiods in which the change in appearance from a prior frame isdetermined to be great, an image is acquired wherein the number ofpixels is the same as the number of pixels acquired during the displayof preview images (i.e., no reduction of image data). Thus, aphotographic recording of a specimen can be accomplished with asufficiently high resolution during periods in which the change inappearance of the specimen is great. In addition, if the binning mode isselected for a relatively dark specimen (such as where the specimen isimaged using fluorescence from the specimen after the specimen has beenilluminated with excitation light), the signal-to-noise ratio of thedetected light will increase with binning, this being an inherentfeature of binning processing. This enables a high resolution image tobe obtained without increasing the intensity of the excitation light.Thus, damage to a specimen resulting from exposure to too high anintensity of excitation light can be minimized.

Moreover, in Embodiment 1, when S is greater than the specifiedthreshold value, and the binning mode is selected using 2×2 binning, thesignal strength output of the image pickup element 202 will be fourtimes that obtained without binning processing. However, it is alsopossible to provide a signal strength output of the image pickup element202 during binning processing with the signal strength being the same asthat obtained without binning processing, in which case the exposuretime will be longer but the noise level of the output signals from theimage pickup element 202 will be reduced by a factor of 4.

Embodiment 2

The characteristic feature of this embodiment is that the illuminationlight of the microscope 101 is adjusted corresponding to a changed stateof the specimen.

FIG. 10 is a block diagram that shows the components of Embodiment 2 ofa microscope system 100A that includes all the components ofEmbodiment 1. Additionally, Embodiment 2 includes an illuminationcontroller 1001. In order to avoid redundant descriptions of identicalcomponents, only the illumination controller 1001 and its operation willbe described for this embodiment.

The illumination controller 1001 is electrically connected to themicroscope 101 in order to control the amount of illumination light thatis incident onto a specimen. For example, neutral density filters may beselectively inserted into the light path so as to control the amount ofillumination onto the specimen. The illumination controller 1001 is alsoelectrically connected to the CPU 112 by the control bus 111, and theCPU 112 is electrically connected to, and controlled by, the PC 108.

The operation of Embodiment 2 will now be described, to the extent thatit differs from that of Embodiment 1, with reference to FIG. 5. Morespecifically, since the steps from S501 to S506 of FIG. 5 for thisembodiment are the same as in Embodiment 1, further explanation of thesteps S501-S506 for this embodiment will be omitted.

If a directive to perform either the motion picture acquisition ofimages or the time-lapse photography acquisition of images is sent froman input apparatus 110 to the PC 108 and the PC 108 receives thedirective (step S507), the CPU 112 will receive the photographic imagedata from the PC 108 and will establish the threshold value Th (in stepS508) in the change detector 104 and transmit a signal to the drive 205directing the establishment of binning mode in the drive 205.

In step S509, the PC 108 starts an internal timer simultaneously withthe commencement of transmission of photographic data to the CPU 112,and the CPU 112 transmits photographic control parameters in accordancewith the photographic conditions directed by the PC 108 to thephotographic unit 102. At this time, the CPU 112 also transmits acontrol signal to the illumination controller 1001 that reduces theillumination of the specimen to one-fourth of that which existed for thedisplay of preview images.

At this time, the image pickup element 202 (FIG. 2) photo-electricallyconverts the incident light that has been relayed onto it from themicroscope 101 in accordance with a drive signal generated by the drive205 and outputs image signals. These image signals are processed in thesame manner as described in Embodiment 1 and are subsequently output asdigital signals to the pixel number converter 105 and the changedetector 104.

The change detector 104 calculates the value S in the same manner as inEmbodiment 1, and transmits the result of the comparison (i.e., the Kvalue) along with the threshold value Th to the CPU 112.

As shown in FIG. 11, in the case of there being a large change in thedetected image when two frames are compared (K=1), there is no binningprocessing (none) and pixels are output using the same intensity (I) ofillumination light as used for the display of preview images. On theother hand, in the case of there being a small change in the detectedimage when two frames are compared (K=0), binning processing isperformed (such as 2×2 binning processing using one-fourth the normalamount of illumination light ¼ used for the display of preview images).In this manner, the luminous intensities of the calculated pixels thatare output during binning processing are made to be at the appropriatelevel.

In the case where a frame is to be processed using 2×2 binningprocessing due to the value of K being equal to zero (i.e., a smallchange from the previous frame), and where the next frame is to beprocessed using “no binning” due to the value of K being equal to 1(large change), the CPU 112 transmits a control signal to the drive 205.In response thereto, the drive 205 generates a drive signal thatcontrols the acquiring of images by the image pickup element 202. Inaddition, in the frame following when K changes from 1 (large change) tozero (small change), the CPU 112 transmits a control signal to theillumination controller 1001 and makes the illumination intensity beone-fourth that used for the display of preview images. Thus, in thiscase, the pixel number converter 105 outputs input image data in itsexistent state without executing any processing. Subsequently, the imageinput to the controller 106 detects the completion of photographicrecording by means of the image data flow reaching the PC 108 throughthe interface 107, and the PC 108 detects the completion of photographicrecording by means of an internal timer.

The operation and effect of the second embodiment will now be described.In this embodiment, if there is a sufficient change in the appearance ofthe detected image when two frames are compared (K=1), an image isacquired wherein there is no reduced-data processing and each frame isacquired and output with the maximum number of pixels (sometimes termeda ‘through image’). In the case of there being a small change in theappearance of the detected image when two frames are compared (K=0), animage is acquired wherein binning processing is accomplished and theamount of illumination on the specimen is accordingly reduced so thatthe output level (brightness) of the image data is at an appropriatelevel.

Furthermore, this embodiment is able to acquire photographic images witha high degree of resolution using high levels of illumination during aperiod in which there is a detected change in the appearance of aspecimen, while suppressing the level of illumination during periods ofno detected change (or only minor detected change), in the appearance ofthe specimen. Thus, damage to an illuminated specimen is minimized whileenabling changes that occur rather rapidly over short time periods to berecorded with good resolution.

Embodiment 3

The characteristic feature of this embodiment is that a region of aphotographic image in which a changed state of a specimen is to bemonitored and recorded with good resolution may be varied, with theregion's location being selected by the operator. In this embodiment, achange detector 104A is provided in lieu of using the change detector104 of Embodiment 1.

FIG. 12 shows the components of the change detector 104A that applies tothis embodiment. The change detector 104A differs from the changedetector 104 of Embodiment 1 (shown in FIG. 4) in that it additionallyincludes an address comparator 1201. The address comparator 1201 iselectrically connected as shown in FIG. 12. Address information thatdesignates a specific region of a photographic image that is to bemonitored for change in appearance is input to the address comparator1201 from the CPU 112. In addition, the address comparator 1201generates an address showing which position the input image dataoccupies on a photographic image screen, based on a synchronizationsignal that is input to the address comparator 1201 from the signalprocessor 103. A comparison is made of the generated address of theaddress comparator versus the address information from the CPU 112, andthe state of the image that is output to the difference detector 402 ischanged depending on the results of the comparison.

An explanation of the operation of the third embodiment will now beprovided with reference to FIG. 5. In this embodiment steps S501-S504are the same as in the first embodiment, and thus further explanation ofthese steps will be omitted. In step S505, an operator, while viewing adisplayed image, may indicate a region of particular interest within theimage by means of an input apparatus 110, and the PC 108 will displaythe indicated region on the display 109 of FIG. 1 in a manner as shownin FIG. 13. Simultaneously, address information showing the positionoccupied by the vertical axis of the screen is transmitted to the CPU112.

FIG. 13 shows images that may be displayed on the display 109, which mayinclude an indicated region 1302 that includes the specimen image 1304.The indicated region may be input by an operator using an inputapparatus (e.g., a mouse) to insure that the indicated region containingthe specimen image 1304 is displayed jointly with a specimen 1303 duringthe display of preview images on the image display screen 1301. At thistime, the CPU 112 of FIG. 10 transmits address information of theindicated region to the address comparator 1201.

Referring again to FIG. 5, when a photographic conditions change commandoccurs in step S505, the photographic parameters are changed in stepS506 from those used for acquisition of images during the display ofpreview images. After adjusting the photographic parameters for aspecific image, the steps S507-S509 are the same as in Embodiment 1.Therefore, further explanation of these steps will be omitted.

Referring to FIGS. 1 and 12, specimen image data obtained by thephotographic unit 102 (in response to control parameter data from theCPU 112) undergoes various image processing in the signal processor 103as described previously and is output to the change detector 104A (FIG.12) and the pixel number converter 105.

Referring to FIG. 12, an address comparator 1201 within the changedetector 104A compares the position address of the image data that isreceived from the signal processor 103 with the address information sentby the CPU 112. When there is conformance, image data is output from thedifference detector that is identical to the image data input into thechange detector 104A; when there is no conformance, image data having anillumination value of “0” is output to the difference detector 402(i.e., no image data is output).

As before, the difference detector 402 calculates the frame-integratedvalue S of the illumination difference between successive frames in thesame manner as in Embodiment 1 and outputs the frame-integrated value Sto the threshold value discriminator 403. The threshold valuediscriminator 403 transmits to the CPU 112 the comparison result signalK after comparing the threshold value Th and the integrated value S, andoutputs image data corresponding to the selection signal SEL (where SELis directed from the CPU 112) to the controller 106 for storing motionpicture images or time-lapse photography images in the PC 108. Thisoccurs via the interface 107. Since the further steps (through thecompletion of photographic recording in step S511) are the same as inEmbodiment 1, these steps will not be further discussed.

An explanation of the results of the operation of the third embodimentwill now be provided. Assume that there are multiple items that arewithin a microscope's field of view on a photographic screen. Forexample, assume that there are two specimens 1303 and 1304 as shown inFIG. 13. Assume that the operator selects a region for the apparatus tomonitor and record the state of change of one of the specimens, in thiscase the region 1302. If region 1302 (which includes the specimen 1304),is indicated by the operator, the change detector 104A will detectchanges in the specimen, and will calculate the frame-integrated value Sof the illumination difference signal of two successive frames on arepeating basis using the illumination values of the region 1302. Thus,even if there is change in the specimen 1303 (since the specimen 1303 isnot within the region being monitored for changes in appearance) onlythe state of change of the specimen 1304 that is within the designatedregion 1302 (i.e., the object of interest) will be recorded with highresolution. In this manner, photographic image data can be obtained withhigh resolution of a region of interest when there is a change inappearance of a specimen within the region interest, without generatingunwanted photographic image data even where an uninteresting specimenwithin the view field of the microscope but outside the designatedregion of interest changes in appearance

Embodiment 4

The characteristic feature of the fourth embodiment is that it changesthe compression ratio of the photographic image in a manner thatcorresponds to a changed state of a specimen.

FIG. 14 shows the components of the fourth embodiment 100B of thepresent invention. The components of Embodiment 4 are the same as inEmbodiment 1 except that a compression unit 1401 replaces the pixelnumber converter 105 shown in FIG. 1. In this embodiment as well, themicroscope 101 is capable of switching, for example, to a transparentfield observation state and to a state that corresponds to each type ofmicroscopic observation, such as fluorescent observation and the like.As before, further explanation of like components will not be given.

As shown in FIG. 14, the compression unit 1401 is electrically connectedvia the control bus 111 to the signal processor 103, the change detector104, the controller 106, and the CPU 112. Image data is input to thecompression unit 1401 from the signal processor 103, and the comparisonresult signal K is input to the compression unit 1401 from the changedetector 104. Image data may be output from the compression unit 1401 tothe controller 106 without being compressed. Also, images that have beencompressed by the compression unit 1401 using one of a compression ratioA (large compression ratio) or a compression ratio B (small compressionratio), depending on the comparison result obtained from the changedetector 104, may be output to the controller 106.

An explanation will now be provided of the operation of Embodiment 4with reference to FIG. 5. Steps S501 through S504 are the same as inEmbodiment 1, and thus further explanation of these steps will beomitted. Also, at this time, the change detector 104 does not operate,and the compression unit 1401 outputs to the controller 106 image datawith “through processing” (i.e., without processing data that has beeninput from the signal processor 103).

If motion picture recording for a specified period of time is directed(in step S507), the PC 108 initially transmits control data to the CPU112 via the interface 107. At the same time that the CPU 112 establishes(in step S508) the threshold value Th for the received image data in thechange detector 104, a signal is sent indicating a high compressionratio A should be used in the compression unit 1401.

In step S509, the PC 108 starts an internal timer and simultaneouslytransmits control data to the CPU 112 that directs the commencement ofphotographic recording, at which time the change detector 104 commencesoperation. At this time, light from the microscope 101 that is incidenton the image pickup element is photo-electrically converted by the imagepickup element 202 and is processed in the same manner as for thedisplay of preview images, and is output to the compression unit 1401and the change detector 104.

The change detector 104, as in the Embodiment 1, calculates theframe-integrated value S of the illumination difference betweensuccessive frames. As before, in the threshold value discriminator 403,a comparison is made of the frame-integrated value S of the illuminationdifference versus a threshold value Th. If S is greater than or equal toTh, a comparison result signal K having a value of “1” is transmitted tothe compression unit 1401 and the CPU 112 as a digital signal. If not, acomparison result signal K having a value of “0” is similarlytransmitted to the compression unit 1401 and the CPU 112. However, sincean initial first frame does not have data of a previous frame, a signalK having a value of “0” is initially output.

Depending on the value of the comparison result signal K that isreceived, the compression unit 1401 compresses the image using acompression ratio as shown in FIG. 15. In other words, when theintegrated value S is determined to be greater than or equal to theestablished threshold value Th (i.e., K=1), the image is compressed witha small compression ratio B and the output is sent to the controller106. On the other hand, if the integrated value of S is determined to besmaller than the threshold value of Th, (i.e., K=0), the image data iscompressed with a large compression ratio A and the output is sent tothe controller 106. Subsequently, the image data transmitted to thecontroller 106 is transmitted to PC 108 via the interface 107 until aninternal timer of the PC 108 detects that a specified period of time haselapsed. Since the operation to the completion (in step S511) of motionpicture recording using a specific file format is the same as inEmbodiment 1, further explanation of these steps will be omitted.

An explanation will now be provided concerning the operation and resultsof Embodiment 4. In Embodiment 4, if the frame-integrated value S of theillumination difference between successive frames is determined to begreater than or equal to an established threshold value Th (i.e., if thecomparison result signal K equals 1), the change state of the specimenwill be detected as being great and image data will be created in whichthe image is compressed using a small compression ratio B. On the otherhand, if the frame-integrated value S of the illumination differencebetween successive frames is determined to be smaller than theestablished threshold value Th (i.e., if K=0), then the changed state ofthe specimen will be detected as being small and image data will becreated in which the image is compressed with a large compression ratioA. Therefore, an image of high-quality (i.e., low compression) can berecorded during a period in which the appearance of a specimen changes.

Embodiment 5

The characteristic feature of this embodiment is changing theframe-thinning ratio of image acquisition depending on a changed stateof a specimen. FIG. 16 shows the components of the microscope system100C according to Embodiment 5 of the present invention, whichcomponents are the same as in Embodiment 1 except that a frame-thinningunit 160.1 is substituted for the pixel number converter 105. Also, theelectrical connections of components of this embodiment are the same asin Embodiment 1 once the frame-thinning unit 1601 is substituted for thepixel number converter 105. Therefore, redundant explanations of theseitems will be omitted. The frame-thinning unit 1601 is provided with aninternal counter (not illustrated) that counts the frame numbers usingthe synchronization signal. The frame-thinning unit 1601 reads thecomparison result signal K from the frame change detector 104 using thesynchronization signal, based on its frame counter value. As shown inFIG. 17, the input image data from the signal processor 103 is processedusing either N frame cycle thinning or no-thinning, and is then outputto controller 106.

The operation of Embodiment 5 will now be described with reference toFIG. 5. An explanation of steps S501 through S506 will be omitted sincethese steps are the same for Embodiment 5 as described for previousembodiments. However, during steps S501 through S506, the changedetector 104 is not operated and no thinning of the image data inputfrom the signal processor 103 is accomplished in the frame-thinning unit1601. Therefore, image data is acquired and output to controller 106 inthe same manner as for the display of preview images.

If the commencement of either (1) motion picture image acquisition or(2) time-lapse photography acquisition for image recording is directed(in step S507) for a specified period of time, initially the PC 108transmits the photographic image data to the CPU 112, which in turnestablishes (in step S508) the threshold value Th in the change detector104 corresponding to received photographic image data. At the same time,a signal is sent to the frame-thinning unit 1601, directing N framesynchronized thinning of the image data that is suitable for datareduction.

In step S509, the PC 108 starts an internal counter and simultaneouslytransmits photographic image data directing the commencement ofphotographic recording to the CPU 112. At this time, the change detector104 commences operation. Incident light from the microscope 101 isphoto-electrically converted by the image pickup element 202 into asignal that is then processed in the same manner as for the display ofpreview images, and is output to the frame-thinning unit 1601 and thechange detector 104.

The change detector 104 calculates the value S in the same manner as inEmbodiment 1. A comparison is then made with the threshold value Th inthe threshold value discriminator 403. As before, if the value of theframe-integrated value signal S is greater than or equal to Th, acomparison result signal K is made equal to “1” and transmitted to theframe-thinning unit 1601 and the CPU 112 as a digital signal. Otherwise,the comparison result signal K is made equal to “0” and is transmittedto the frame-thinning unit 1601 and the CPU 112 as a digital signal. Asbefore, since the initial first frame does not have data of a previousframe, a value of K equal to “0” is initially output.

The frame-thinning unit 1601 accomplishes frame-thinning depending onthe output signal K of the change detector 104 as set forth in FIG. 17.In other words, if the signal K is “1”, images are transmitted withoutthinning. On the other hand, if the signal K is “0”, (i.e., there islittle change in appearance between successive frames), thinned images(that are thinned during a cycle of N frames) are output to thecontroller 106.

Subsequently, the image data transmitted to the controller 106 istransmitted to PC 108 via the interface 107 until the end of the periodof photographic recording established by the internal timer of PC 108 isdetected. In the PC 108, since the operation to the completion (in stepS511 of FIG. 5) of the series of photographic operations that isaccomplished in a specific motion picture file format is the same asthat of Embodiment 1, redundant explanation of these steps will beomitted.

An explanation will now be provided concerning the operation and resultsof Embodiment 5. FIG. 18 illustrates the frame-integrated value S thatis calculated in the change detector 104, the threshold value Th, andthinning processing that occurs in the frame-thinning unit 1601 of thisembodiment. In this instance, the frame thinning cycle has a duration offive frames, and the thick vertical lines shown in FIG. 18 are frames inwhich image data is output.

Since in frame 0 (i.e., before frame 1), the fifth frame, and the 15thframe it is detected that K equals “0” (i.e., in these frames the changein appearance of the specimen as compared to the previous frame is suchthat S<Th), thinning processing subsequently takes place in frames 1-4,6-9, and 16-19. On the other hand, since frame 10 is such that S>Th, thespecimen change is detected as being great and thus K is set to “1”.Therefore, the subsequent frames 11-14 are output without thinningprocessing.

According to this embodiment, photographic images are not acquired (andthus are not recorded) during periods in which observations are notdesired, in other words, during periods in which there is no change inthe specimen state. However, during periods of interest to an observer(i.e., when the specimen state is changing), photographic images areacquired without thinning processing. Thus, images are recorded at ahigh frame rate (i.e., at short intervals) during periods of interest toan observer, thereby enabling efficient photographic recording withminimal needless use of storage capacity.

Embodiment 6

The characteristic feature of Embodiment 6 is that multiple thresholdvalues may be selected by the operator for recording the state of changeof a specimen. FIG. 19 is a block diagram showing the components of thechange detector 104B according to this embodiment. The change detector104B differs from the change detector 104 of Embodiment 1 in that thechange detector 104B includes a threshold value selector 1901. Thethreshold value selector 1901 is electrically connected via the controlbus 111 to the CPU 112, and it is also electrically connected to thethreshold value discriminator 403. The threshold value selector 1901houses a register (not shown) that stores multiple threshold values (Th1, Th 2, . . . Th N), which are respectively designated by the CPU 112through the control bus 111. Also, the threshold value selector iselectrically connected to the output end of the respective registers,and selected threshold values (any of Th 1, Th 2, . . . Th N) are outputto the threshold value discriminator 403 by means of a threshold valueselection signal SEL from the CPU 112.

The operation of this embodiment will now be described with reference toFIG. 5. Steps S501-S506 of this embodiment are the same as those of thefirst embodiment, and thus further explanation of these steps will beomitted, except to note that in this embodiment the change detector 104does not operate. In this embodiment, if motion picture photographicrecording is directed (in step S507) for a specified period, the PC 108will transmit image data to the CPU 112, which establishes multiplethreshold values (Th 1, Th 2, . . . Th N) in the internal register ofthe threshold value selector 1901 corresponding to the received data.Next, the PC 108 displays the multiple threshold values (Th 1, Th 2, . .. Th N) that have been established by the threshold value selector 1901on the display 109. If any of the displayed threshold values areselected (by the operator using the input apparatus 110), the CPU 112transmits a threshold value selection signal SEL to the PC 108. If aselected threshold value (provisionally assumed to be Th a) is output tothe threshold value discriminator 403, the threshold value setting iscompleted (in step S508). At the same time, a signal SEL (which directseither thinning or binning) is transmitted to the pixel number converter105 and to the drive 205.

Since the steps from when the PC 108 (in step S509) starts an internaltimer and simultaneously transmits image data directing the commencementof photography to the CPU 112 until the completion of photographicrecording (in step S511) are the same as in Embodiment 1, furtherexplanation of these steps will be omitted.

The operation and results of this embodiment will now be discussed. FIG.20 illustrates the manner in which the frame-integrated value S of theillumination difference that is calculated and output from thedifference detector within the change detector 104B of FIG. 19 changeswith frame number during successive frames at a time of bright fieldobservation. Generally, with bright field observation the image of aspecimen is brighter, and thus an adequate exposure can be obtainedwithout elevating the gain of the image pickup element. Therefore, theamount of noise in the recorded photographic images is small.Furthermore, even when a low threshold value (Th 1) is established,minute changes in the specimen can be detected without erroneouslydetecting noise components as a specimen change event.

FIG. 21 illustrates the manner in which the frame-integrated value S ofthe illumination difference that is output from the difference detectorwithin the change detector 104B of FIG. 19 changes with frame numberduring successive frames at a time of fluorescent light observation.Generally, with fluorescent light observation, the image of a specimenwill be relatively dark since the excitation light should be weak inorder to prevent photobleaching of the specimen. Therefore, in order toprovide a proper exposure, the gain of the image pickup element isincreased relative to that used for bright field observation. Thisgenerates optical ‘noise’ in the displayed image. If the threshold valueTh is established to be low (Th 1), the possibility of erroneouslydetecting noise components as a change in appearance of the specimen ishigh. Therefore, a high threshold value (Th 2) that is higher than thethreshold value Th 1 is established in the case of fluorescent lightobservation, and erroneous detection of noise components can be reduced.Furthermore, according to this embodiment, since the threshold value Thmay be selected from among multiple levels depending on the microscopeexamination method employed, optimal photographic image recording can beobtained.

The invention being thus described, it will be obvious that the same maybe varied in many ways. For example the binning mode in Embodiments 1-3and 6 is not restricted to the 4-pixel calculation of 2×2 pixel arrays,but changes are also possible relative to a 16-pixel calculation of 4×4pixel arrays, or a 64-pixel calculation of 8×8 pixel arrays (as well asother binning arrangements). The exposure time at this time incomparison to when there is no binning is further shortened to 1/16thand 1/64th, respectively. For this reason, at the time of observing adark specimen with fluorescent light, it is possible to acquire anadequate frame rate for motion picture photographic recording using asufficiently short exposure time. In addition, in Embodiment 3, thedesignated regions are not restricted to rectangular regions.Furthermore, the number of designated regions of interest is notrestricted to just one, as multiple regions of interest may also bedesignated. In this manner, the designated regions may be flexiblyestablished corresponding to complex changes in a specimen. In addition,the compression ratio in Embodiment 4, the photographic interval inEmbodiment 5, and the multiple threshold values of Embodiment 6 are notrestricted to the types discussed above. For example, by establishingrespective compression ratios relative to multiple threshold values inEmbodiment 6, appropriate photographic images can be recorded relativeto various photographic environments. Such variations are not to beregarded as a departure from the spirit and scope of the invention.Rather, the scope of the invention shall be defined as set forth in thefollowing claims and their legal equivalents. All such modifications aswould be obvious to one skilled in the art are intended to be includedwithin the scope of the following claims.

1. An image acquisition apparatus for use with a microscope comprising:an image pickup element that acquires images obtained using themicroscope; a change detector that detects the amount of change betweenan image acquired by the image pickup element and a subsequent imageacquired by the image pickup element; and a binning means that performsbinning processing by calculating and outputting cumulative pixelinformation of multiple proximate pixels of an input image as an outputpixel so as to form a reduced-data output image, or that outputs pixelinformation of an input image as output data without reduced-dataprocessing, based on the amount of change detected by the changedetector; wherein reduced-data images as well as images that have notbeen reduced are output from the image acquisition apparatus.
 2. Theimage acquisition apparatus of claim 1, and further comprising: athinning means that performs thinning processing by outputting onlyspecified pixels from among multiple proximate pixels of an input imageor deletes one or more entire frames of pixels so as to formreduced-data output images, or that outputs the input image withoutperforming reduced-data processing, based on the amount of changedetected by the change detector; and a selection means that selectivelyexecutes either binning processing or thinning processing as the type ofdata-reduction processing to be performed by the image acquisitionapparatus based on a specified value; wherein reduced-data images aswell as images that have not been reduced are output from the imageacquisition apparatus.
 3. The image acquisition apparatus of claim 1,and further including an address comparator that enables a region of animage to be designated by the operator for which the change detectordetects the amount of change within said region.
 4. The imageacquisition apparatus of claim 2, and further including an addresscomparator that enables a region of an image to be designated by theoperator for which the change detector detects the amount of changewithin said region.
 5. The image acquisition apparatus of claim 1,wherein a threshold value that is used by the change detector may beselected from among multiple values.
 6. The image acquisition apparatusof claim 2, wherein a threshold value that is used by the changedetector may be selected from among multiple values.
 7. An imagerecording system comprising: the image acquisition apparatus as setforth in claim 1; a microscope that provides images of a specimen asinput to said image acquisition apparatus; and a storage means thatstores image data output by said image acquisition apparatus.
 8. Animage recording system comprising: the image acquisition apparatus asset forth in claim 2; a microscope that provides images of a specimen asinput to said image acquisition apparatus; and a storage means thatstores image data output by said image acquisition apparatus.
 9. Animage recording system comprising: the image acquisition apparatus asset forth in claim 3; a microscope that provides images of a specimen asinput to said image acquisition apparatus; and a storage means thatstores image data output by said image acquisition apparatus.
 10. Animage recording system comprising: the image acquisition apparatus asset forth in claim 4; a microscope that provides images of a specimen asinput to said image acquisition apparatus; and a storage means thatstores image data output by said image acquisition apparatus.
 11. Theimage recording system of claim 7, wherein the image acquisitionapparatus acquires images at a slower rate than the rate used forordinary motion picture photography so that time-lapse images arerecorded.
 12. The image recording system of claim 8, wherein the imageacquisition apparatus acquires images at a slower rate than the rateused for ordinary motion picture photography so that time-lapse imagesare recorded.
 13. The image recording system of claim 7, and furtherincluding an illumination controller that enables an illumination on theobject to be controlled so that, during binning processing of imagedata, the illumination is reduced as compared with that for thinningprocessing.
 14. The image recording system of claim 8, and furtherincluding an illumination controller that enables an illumination on theobject to be controlled so that, during binning processing of imagedata, the illumination is reduced as compared with that for thinningprocessing.
 15. An image acquisition apparatus for use with a microscopecomprising: an image pickup element that acquires images obtained usingthe microscope; a change detector that detects the amount of changebetween an image acquired by the image pickup element and a subsequentimage acquired by the image pickup element; and a compression means thatcompresses observed pixels acquired by the image pickup element; whereina compression ratio of the compression means is changed to accomplishcompression of data output by the image acquisition apparatus based onthe amount of change detected by the change detector.
 16. An imagerecording system comprising: the image acquisition apparatus as setforth in claim 15; a microscope that provides images of a specimen asinput to said image acquisition apparatus; and a storage means thatstores image data output by said image acquisition apparatus.
 17. Theimage recording system of claim 16, wherein images are acquired at aslower rate than for ordinary motion picture photography so thattime-lapse images are acquired.
 18. An image storage method for storingphotographic images of an object that is observed with a microscope,said method comprising the following steps, performed in the orderindicated: (a) acquiring images obtained using the microscope by usingan image pickup element to pick up relayed images from the microscope;(b) detecting the amount of change between an image acquired by theimage pickup element and a subsequent image acquired by the image pickupelement; and (c) performing reduced-data processing according to one ofthe sub-steps (1) or (2) below, or outputting an input image withoutperforming reduced-data processing, based on the amount of changedetected in step (b), wherein one of the substeps (1) or (2) is selectedbased on a specified value: (1) performing binning processing bycalculating cumulative pixel information of multiple proximate pixels ofan input image and outputting an output pixel so as to form areduced-data output image, or (2) performing thinning processing byoutputting only specified pixels from among multiple proximate pixels ofan input image so as to form a reduced-data output image; (d) storingimages that include reduced-data images produced by sub-steps (c1) or(c2) above as well as images that are acquired in step (a) above thatare not subject to data-reduction.
 19. An image storage method forstoring photographic images of an object that is observed with amicroscope, said method comprising the following steps, performed in theorder indicated: (a) acquiring images obtained using the microscope byusing an image pickup element to pick up relayed images from themicroscope; (b) detecting the amount of change between an image acquiredby the image pickup element and a subsequent image acquired by the imagepickup element; (c) performing reduced-data processing using acompression means that compresses observed pixels acquired by the imagepickup element; and (d) storing image data output by the compressionmeans; wherein a compression ratio of the pixel information is changedusing the compression means based on the amount of change detected instep (b) above.
 20. The image storage method of claim 19, wherein imagesare acquired at a slower rate than for ordinary motion picturephotography so that time-lapse images are acquired.